Conventionally, a brake device is known which is equipped with a master cylinder and a mechanical type servo pressure generating portion, etc., as disclosed, for example, in a Japanese Patent Publication 2011-240873 A. Further, a brake device which is equipped with a mechanical regulator for generating a hydraulic pressure in a servo chamber corresponding to a pilot pressure based on an accumulator pressure in an accumulator is disclosed in another Japanese Patent Publication 2013-193619 A. There is also disclosed a device which controls the wheel cylinder pressure by an opening and closing of the electromagnetic valves without using a regulator. According to these conventional brake devices, a target pressure for a brake operating amount is preset with respect to the servo chamber or the wheel cylinder and an actual pressure (actual pressure in the servo chamber or the wheel cylinder) is controlled to be the target pressure (target pressure in the servo chamber or the wheel cylinder).
According to these conventional brake devices, for example, as disclosed in a Japanese Patent Publication 2009-40376 A, a predetermined dead zone is preset for the target pressure. A brake device recognizes that the pressure has reached substantially to the target pressure when the actual pressure enters into the dead zone (dead zone range) upon hydraulic pressure control. By setting such dead zone, hunting of the hydraulic pressure control can be more suppressed than in a case of setting the target pressure to one point.